why are my date functions not working

Today, but not before, as far as I can remember, when I put a date function into a sheet it does not evaluate but stays as the formula including the =. This seems to involve most date functions including Today(), Now(), Day, Month. It seems as if I have caused this during this mornings work. Non date functions seem all to be still working. What have I done?
John

Check that the cells are not formatted as text.
Also check that you don not have "Show formulas" selected.

Thanks for your interest in my problem. At first I thought your suggestion that some formulas may be formatted as text was going to be the answer as I had formatted some of the cells containing date formulas as so that the result would appear as a number. But most of the affected formulas are not text. The "Show Formulas" had not been clicked. The problem is now showing on non date formulas as simple as "=Sheet1!A1". I am now quite worried as I see more and more of my work becoming non functional!
John

Can you post a sample workbook that shows the problem.

Here is the sample, still showing the fault.
It might be a bit confusing so I will explain the method. In order to reduce the size of a workbook I use the sub PastedownN which is included.
This means I can use 1 row or column of formulas and copy these across big areas of a sheet as text. There are two formulas and 2 results on the attached sheet
John

Thanks for that. The only thing I can think of is that when the formulae were put into the cells, they were formatted as text. If you click on any of the cells press F2 & than enter, the formulae work.

Thanks for your suggestion. What do I reformat them as? Date or number ?
John

Which ever you want.